import type { Ref } from "vue";
import { ref } from "vue";
import { addClass, hasClass, prefixStyle } from "../utils/dom";
import type { WaterfallProps } from "../types/waterfall";
import type { CssStyleObject, Nullable } from "../types/util";

const transform = prefixStyle("transform");
const duration = prefixStyle("animation-duration");
const delay = prefixStyle("animation-delay");
const transition = prefixStyle("transition");
const fillMode = prefixStyle("animation-fill-mode");

export function useLayout(
  props: WaterfallProps,
  colWidth: Ref<number>,
  cols: Ref<number>,
  offsetX: Ref<number>,
  waterfallWrapper: Ref<Nullable<HTMLElement>>
) {
  const posY = ref<number[]>([]);
  const wrapperHeight = ref(0);

  // 获取对应y下标的x的值
  const getX = (index: number): number => {
    const count = props.hasAroundGutter ? index + 1 : index;
    return props.gutter * count + colWidth.value * index + offsetX.value;
  };

  // 初始y
  const initY = (): void => {
    posY.value = new Array(cols.value).fill(
      props.hasAroundGutter ? props.gutter : 0
    );
  };

  // 添加入场动画
  const animation = addAnimation(props);

  // 排版
  const layoutHandle = async () => {
    // 初始化y集合
    initY();

    // 构造列表
    const items: HTMLElement[] = [];
    if (waterfallWrapper && waterfallWrapper.value) {
      waterfallWrapper.value.childNodes.forEach((el: any) => {
        if (el!.className === "waterfall-item") items.push(el);
      });
    }

    // 获取节点
    if (items.length === 0) return false;

    // 遍历节点
    for (let i = 0; i < items.length; i++) {
      const curItem = items[i] as HTMLElement;
      // 最小的y值
      const minY = Math.min.apply(null, posY.value);
      // 最小y的下标
      const minYIndex = posY.value.indexOf(minY);
      // 当前下标对应的x
      const curX = getX(minYIndex);

      // 设置x,y,width
      const style = curItem.style as CssStyleObject;

      // 设置偏移
      if (transform) style[transform] = `translate3d(${curX}px,${minY}px, 0)`;
      style.width = `${colWidth.value}px`;

      // 更新当前index的y值
      const { height } = curItem.getBoundingClientRect();
      posY.value[minYIndex] += height + props.gutter;

      // 添加入场动画
      animation(curItem, () => {
        // 添加动画时间
        if (transition) style[transition] = "transform .3s";
      });
    }

    wrapperHeight.value = Math.max.apply(null, posY.value);
  };

  return {
    wrapperHeight,
    layoutHandle,
  };
}

// 动画
function addAnimation(props: WaterfallProps) {
  return (item: HTMLElement, callback?: () => void) => {
    const content = item!.firstChild as HTMLElement;
    if (content && !hasClass(content, props.animationPrefix)) {
      const durationSec = `${props.animationDuration / 1000}s`;
      const delaySec = `${props.animationDelay / 1000}s`;
      const style = content.style as CssStyleObject;
      style.visibility = "visible";
      if (duration) style[duration] = durationSec;

      if (delay) style[delay] = delaySec;

      if (fillMode) style[fillMode] = "both";

      addClass(content, props.animationPrefix);
      addClass(content, props.animationEffect);

      // 确保动画完成后item可见
      setTimeout(() => {
        const itemStyle = item.style as CssStyleObject;
        itemStyle.visibility = "visible";
        if (callback) callback();
      }, props.animationDuration + props.animationDelay);
    }
  };
}
